Preparation of resinous reaction products of sulphur dioxide and olefins



Patented Mar. 5, 1 940 PREPARATION OF RESINOUS REACTION PRODUCTS 0FSULPHUR OLEFINS DIOXIDE AND Frederick E. Frey, Bartlesville, 0kla., andLouis H. Fitch, Jr., deceased, late of Bartlesville, 0kla., by FirstNational Bank in Bartlesville, administrator, Bartlesvllle, 0kla.,assignors to Phillips Petroleum Company, Bartlesvillc, Okla., acorporation of Delaware No Drawing.

Original application March 16,

1932, Serial No. 599,350. Divided and this application September 6,1938, Serial No. 228,700

6 Claims.

phur dioxide and oleflns, and to catalysts for effecting such reactions.The invention also relates to a method of molding-the solid products ofthe olefin-sulphur dioxide reaction.

The present application is a division of our co pending applicationSerial Number 599,350, filed March 16, 1932, now Patent No. 2,128,932.

A primary object of the invention is the-provision of catalysts adaptedto enhance the reaction between sulphur dioxide and olefins, and tocause such reaction to take place rapidly even in complete darkness.

A further object of the invention is the provision of a heat-pressuremolding process for the production of coherent resinous products fromthe reaction products of sulphur dioxide and olefins.

Additional objects will become apparent as the description of theinvention proceeds.

While the reaction between sulphur dioxide and certain olefins to form aresin-like product is known, the reaction as therein described, takesplace readily only in the presence of sunlight or some other source ofactinic light.

Heat alone has been found to be of but limited effectiveness in bringingabout interaction between sulphur dioxide and olefins to form aresinlike product. Many olefins which react rapidly with sulphur dioxidein the presence of light, do not react readily in the dark, even attemperatures somewhat in excess of 100 C.

According to the present invention, the reaction can be made to takeplace incomplete darkness in the presence of small amounts of chemicalagents which exert a catalytic eifect. It has been found that by theaddition of suitable catalysts, the preparation of resinous reactionproducts of sulphur dioxide and olefins may be effected at lowtemperatures in comparatively short reaction times, and in the absenceof means for providing actinic light. The catalysts, however, are alsoeffective in conjunction with elevated temperatures and/or light.

The catalysts which are suitable for catalyzing the reaction betweensulphur dioxide and olefins under the conditions outlined-are oxygen,organic peroxides, salts of silver and monovalent copper, nitric oxide,and nitrogen dioxide. Silver sulphate and sulphite alsocatalyze thereaction. Cuprous chloride is a catalyst for the reaction.

For example, 2-butene and sulphur dioxide were sealed in liquid mixturein a glass tube with one-half of one percent by weight of benzoylperoxide in solution. The reagents were completely converted into asolid resin on standing for three days in the dark at 80 F. Under thesame conditions, in the absence of a catalyst, 2 -butene and sulphurdioxide failed to react to any appreciable extent in the course of threemonths.

With the same materials and conditions, small quantities of anotherperoxide, 'diethyl peroxide, induced the complete conversion of thereagents to resin in four days. Small quantities of silver nitrateinduced the reaction to completion in thirty minutes. 7

The aforementioned catalysts have been found useful in inducing andaccelerating the reaction of other olefins such as ethylene, propylene,bu-

tene-l, pentene-l, hexene-l, heptene-l, and iso- .propyl ethylene, withsulphur dioxide both in the presence and absence-of light and diluents.The reaction ofdiolefins such as 1,3-butadiene and cyclopentadiene withsulphur dioxide is likewise accelerated by these catalysts.

the catalyst in the product as an impurity. Re-

gardless of how produced, they usually form as a glassy, viscousmaterial in the presence of an excess of sulphur dioxide which dissolvesthe resin, except in the case of ethylene, propylene and some dienes,which yield a resin insoluble in sulphur dioxide.

The polymerization of these materials is no primarilya reaction at thesurface of the catalyst,

but is principally due to the presence of catalyst dissolved in theolefin, S02 mixture. Consequently, any means by which the olefin,sulphur dioxide, and catalyst may be mixed properly, and held at therequisite temperature for a sumcient period of time, is satisfactory forthe formation of the product.

In molding resins obtained in either of the ways indicated in thepreceding paragraph, certain difficulties are encountered. [The resinousmaterials can be melted under ordinary conditions only with considerableswelling and decomposition, and hence cannot be formed into usefulshapes by melting and pouring into molds. The

formation of the resin in the mold, either in the presence or absence ofpressure substantially above the vapor pressure of the reacting mixture,

is not practical, due to .the large volume shrinkage which accompaniesthe chemical reaction and the difiiculty of obtaining a pure and homo-170 C. in a mold under pressures of 200 to 2000 or more pounds persquare inch to produce a vitreous transparent 'or semi-transparentcoherent body 01' good mechanical strength and hardness.

Similarly, the resin produced from propylene and liquid sulphur dioxide,which separates as an insoluble powder from the reaction mixture, may beheated to temperatures of C. to 240 C. in a mold under pressure toproduce a very hard vitreous body varying from opaque to transparentaccording to conditions of temperature and pressure. High pressuresfavor the formation of well fused, transparent and translucent bodies,though the pressures necessary for this purpose vary greatly withthedii'ferent resins.

In the two foregoing examples, the l-butene resin may be molded into atransparent product at suitable temperatures under pressures around 200pounds per square inch, whereas the propylene resin may generally bemore advantageously molded at 2000 pounds per square inch or over.

In general, the mold is cooled before releasing the pressure andremoving the product, but by the selection of the lower moldingtemperatures and pressures sufliclent for the resin under treatment,this cooling may be avoided and the resin removed from the mold atmolding temperature.

The duration of the heat treatment is not usually of primary importance,as in the case of phenol-formaldehyde resins, though it should be longenough to 'enable all the resin to come to a fairly uniform temperature,and short enough to avoid serious decomposition of the resin. The resinmay, however, usually be heated to molding temperature prior to theapplication of pressure without serious decomposition. If the resin tobe molded has been heated to molding tempera.- ture prior to theapplication of pressure, the time required to produce a coherent resinof desired properties need usually not exceed the time required todevelop the desired pressure and, in some cases, cool the mold somewhat.The molding process appears to depend predominantly on a softening orpartial fusion under pressure, though further polymerization during theapplication of heat may also contribute to the formation of asatisfactory product. The application of pressure is necessary notmerely for the shaping of the molded mass, but also to secure properfusion and coherence of the resin particles at temperatures sufficientlylow to avoid serious decomposition of the resin.

The nature of the molded products isdependent upon both the nature ofthe original material and the conditions of heat and pressure treatment.In general, they are colorless or slightly brown, and quite hard andtough, but may be either opaque, translucent or highly transparent. Theresin may be compounded with fillers, dyes, pigments and the like toproduce desired variations inmechanical properties and appearance.

The molded products are similar "chemically to the material used formolding. They are not readily attacked by acids, alkalis or halogens,and

are insoluble in most solvents, although liquid sulphur dioxide is agood solvent for most of them. The products are suitable for a widevariety of uses. a

We claim:

1. The method .of producing high molecular weight heteropolymers ofsulphur dioxide and oleflns which comprises reacting sulphur dioxidewith an olefin in the presence of a small quantity of an oxide ofnitrogen.

2. The method according to claim 1 in which the oxide is nitrogendioxide.

3. The method according to claim 1 in which the oxide is nitric oxide.

4. The process of producing high molecular weight heteropolymers ofsulphur dioxide and oleflns which comprises reacting sulphur dioxidewith oleflns in the absence of actinic light in the presence oi asuflicient amount of an oxide of nitrogen to effect the reaction.

5. The method according to claim 4 in which the oxide is nitrogendioxide.

6. The method according to claim 4 in which the oxide is nitric oxide.

FIRST NATIONAL BANK IN BAR'ILESVILIE, Administrator of the Estate ofLouis H. Fitch,

Jr., Deceased,

By J. F. CRONIN,

Vice-President. FREDERICK E. FREY.

